After beat metronome



` May 16, 1967v A. s;- PANDE` ETAL 3,320,508

` l AFTER BEAT METRONOME Filed June 8, 1964 2 Sheets-Sheet;

OFF 'SINGLE n1 AFTER BEATS `"-'|H||||||| BEATS I l Y l2 3 NUMBERIINHN" DOWN BEAT FULSES V 7a TRIGGER PULSE DIFFERENTIATED TRIGGER PULSE INVENTORJS) v .071 *3** GORDON D. BROWNINGl ALBERT s. PANDE May 16, 1967 A. s. PANDE ETAL 3,320,508

AFTER BEAT METRONOME Filed June 8, 1964 2 Sheets-vheet 2 INVENTOMS) GORDON D. BROWNING ALBERT S. PANYDE United States Patent Office 33,320,608 Patented May 16, 1967 3,320,608 AFTER BEAT METRONOME Albert S. Pande, 6776 Thornhill Drive, Galtland, Calif. 94611, and Gordon D. Browning, 19056 Stanton Ave., Castro Valley, Calif. 94546 Filed June 8, 1964, Ser. No. 373,386 3 Claims. (Cl. 340-384) This invention relates generally to metronome devices, and more particularly to such devices as are equipped for selective variation of the characteristics of the sound pulses produced by the device.

In addition to their well known use by musicians, metronomes nd other varied utilization las for example in accompanying calisthenics, dancing, or similar physical activities. In many of the instances requiring rhythm enunciation, it is desirable that the audible sounds or beats have distinguishable sound characteristics, to define what often are referred to as down beats and after beats. Thus, the music teacher or calisthenic leader in vocally setting a rhythm will often emphasize a down beat and then follow this by one or more less pronounced after beats to establish the desired rhythm. The overall repetition rate as Well as the number of after beats for each down beat may vary over a relatively wide range in accordance with the various needs of a given situation.

Accordingly, it is .an object of the present invention to provide a metronome device for providing down beat sound pulses, followed by one or more audibly distinguishable after beat sound pulses,

Another object of the invention is to provide a metronome device for providing down beat sound pulses, followed by one or more audibly distinguishable after beat sound pulses. Another object of the invention is to provide a metronome of the type described in which manually operated means .are provided for readily selecting different numbers of after beats, for varying the repetition rate of the down beats and after beats, and for changing the mode of operation of the devi-ce to function either with or without after beats. l

A furthe-r object of the present invention is to provide an after `beat metronome ofthe type described constructed with simple electronic circuitry utilizing relatively few and inexpensive components, yet which provides reliable and high quality operation.

The invention possesses other objects and features of advantage, some of which of the foregoing will be set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of this specification. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawings (2 sheets):

FIGURE 1 is a perspective external View of a device embodying the present invention.

FIGURE 2 is `a schematic `diagram of an electrical circuit included in a preferred embodiment of the invention.

FIGURE 3 is .a series of graphs depicting functional operation of certain portions of the cincuit shown in FIG- URE 2.

The preferred embodiment of the invention shown in the accompanying drawings generally comprises means for producing a plurality of spaced primary sound pulses, sometimes referred to hereinafter as down beats, means for selectively varying the repetition rate of said pulses, means for producing a repetitions time sequence of a plurality of secondary sound pulses at least one of which is interposed in time between successive ones of said primary pulses, said secondary pulses being audibly distinguishable from said primary pulses and being sometimes hereinafter referred to as after beats.

The general function of the instant after beat metronome is best described with respect to FIGURE 1, wherein is shown a housing 11 having a dial face 12 With a rotatable knob 13 mounted for use in conjunction with the dial face. A switch 14 is provided for selecting the mode of operation of the metronome, being movable into position for either single beats or for down beats and after beats. The switch 14 also is movable to an ofi position for controlling the electrical power supplies. Another switch 16 is movable to three positions to select the number of after beats when the switch 14 is positioned for the after beat mode of oper-ation. A speaker 17 produces audible sound pulses which comprise the down beats and after beats.

In -more detail, the dial face 12 includes an outer dial 18 which as shown in calibrated between 12 to 1'20 and represents the number of beats per minute when the metronome is in its single beat mode of operation. That is, the knob 13 selects the repetition rate of sound pulses from the outer dial 18 when the switch 14 is positioned for single beats, and the pulses produced .are all of the same audible characteristics,

The dial face 12 also includes an inner dial 19 which as shown in calibrated between 6 to 60 and represents the number of major beats -per minute when the metronome is in its .after beat mode of operation. More specifically, when the switch 14 is positioned for after beats, the knob 13 selects the repetition rate of the down beats and the switch i6 selects the number of after beats to be interposed between each of the down beats. Thus, for example, if the knob 13 is pointed at 30 on the inner dial, and the switch 16 is positioned for "2 lafter beats, there will be a total of beats per minute, which include a repetitions time sequence of a down beat followed by two evenly spaced audibly `distinguishable after beats. If for example, the knob 13 is at 3 0 on the inner dial, and the switch 16 is at l after beat, there will be a total of 60 beats per minute, which include a `sequence of one down beat and one after beat.

As regards now the illustrated embodiment of the invention for electronically performing the above described functions, reference is made to FIGURE 2 wherein is shown a iirst oscillator circuit 21, which selectively produces the sound pulses for the single beat mode or the pulses for the after beats in the after beat mode, and a second oscillator circuit 22 which produces the pulses for the down beats in the after beat mode. The above noted switch 14 is seen to include four ganged `arms 23, 24, 26 and 27, which are each movable to terminals a, b, and c. The switch arms 26 and 27 respectively control power supplies 28 and 29, with the supplies being off when the arms are connected to the terminals b, and being on when connected to either the terminals a or c.

The knob 13 is seen to lbe represented by a pair of variable resstances 31 and 32, which are ganged together so that regardless of the position of the knob 13 the value of the resistance 31 is a percentage of its maximum value equal to the percentage resistance 32 is of its maximum value. In the preferred embodiment described herein the resistances 31 and 32 are of identical specification so that their values are also always equal. When the switch arm 23 is connected to its terminal c, the device is in its single beat mode and the resistance 31 is coupled to the oscillator 21 to form a part of its RC circuit for controlling the repetition rate of pulses produced. The switch arm 24 when connected to its terminal c shorts out the oscillator 22 to ground, and the resistance 32 is disconnected.

Describing the circuit now with regard to the single beat mode of operation, the oscillator 21 is seen to comprise a generally conventional multivibrator circuit including a pair of transistors 33 and 34 which as shown are of the PNP type and have their emitters connected to ground. The collectors of the two transistors are respectively coupled through resistors 36 and 37 to the supply 28, which as shown is a negative 18 volts. The base of the transistor 33 couples to the supply 28 through the variable resistance 31, while the base of the transistor 34 is coupled to the supply 28 through a fixed resistor 38. A capacitor 39 `couples the lbase of the transistor 34 to the collector -of the transistor 33, while the collector of the transistor 34 is similarly -capacitatively coupled through a capacitor 41 and the switch 23 to the base of the transistor 33.

The oscillator 21 as just described functions in a generally conventional manner and produces an output of a repetitious sequence of pulses, which can be taken off at the collector of the transistor 34 as shown and coupled through a resistor 44 to the base of agate transistor 46. The transistor 46 is powered through its collector by the supply 29, and feeds an output pulse from its emitter through a resistor 47 into an audio oscillator circuit 48. Whenever a pulse from the oscillator 21 triggers the gate 46, the gate causes an audio frequency pulse to be formed in the circuit 48, which is then coupled to the loudspeaker 17 for producing an audible sound pulse of the predetermined frequency.

The audio circuit 48 is seen to include a pair of transistors 49 and 51, of the PNP type as shown, having the respective bases of one coupled to the collector of the other by capacitors 52 and 53. A resistor 54 is coupled between the base of transistor 49 and the supply 29, and a resistor 56 is -coupled between the collector of transistor 49. The collector of the transistor 51 couples through the coil 57 of the speaker 17 to the supply 29, with the input from the gate 46 'being at the base of the transistor 51. The emitter of the transistor 49 is connected to ground and a diode 58 is interposed between ground and the emitter of the transistor 51 for D.C. biasing.

With the switch 14 in the single beat mode, the circuit as just described will produce a series of identical evenly spaced audible pulses from the speaker 17, with the repetition rate controlled by the position of the variable resistance 31.

When the switch 14 is moved into the after beat mode, the switch arms 23 and 24 connect to their respective terminals a, and accordingly, the resistance 32 now becomes coupled into the oscillator circuit 22, which as will be described is substantially identical in basic design to the oscillator 21. The arm of the switch 16 is now operative to select one of the capacitors 41, 42, or 43 to couple between the collector of the transistor 34 and the base of the transistor 33.

As shown, the oscillator 22 includes a pair of transistors 61 and 62, each of which respectively has its base coupled to the collector of the other through the capacitors 63 and 64. Resistors 66 and 67 respectively couple the collectors of the transistors 61 and 62 to the supply 28, and a resistor 68 couples the base of the transistor 61 to the supply 28. The base of the transistor 62 is coupled to the supply 28 through the variable resistance 32, and the oscillator 22 as just described has its output fed from the collector of the transistor 61 through a resistor 69 to the gate 46.

In accordance with the preferred embodiment of the invention, the oscillator 21 is designed to have twice the repetition rate as the oscillator 22 when the switch 16 is in its 1 after' beat position, i.e., coupled to the capacitor 41. Also, the oscillator 22, which provides the down beat pulses, is designedvto produce a pulse of longer duration than the oscillator 21, thereby producing the effect of audibly distinguishable pulses. It is noted that the oscillator 22 triggers the gate 46 to operate the audio oscillator 48 in the same manner as the oscillator 21, except that the longer duration pulse from the oscillator 22 causes 'a longer duration audible sound pulse since the gate 46 is held open for a longer time.

The capacitors 42 and 43 are selected so that when the capacitor 42 is connected, i.e., the switch 16 is in its 2 after beat position, the repetition rate of the oscillator 21 is three times that of the oscillator 22. Likewise, when the cap-acitor 43 is connected for the 3 after beat position of the switch 16, the oscillator 21 has a repetition rate four times that of the oscillator 22,

Further in regard to the foregoing relationships, it is noted that the repetition rate of the oscill-ator 22 is represented by the approximation,

where R represents the variable resistance 32, Cd represents the capacitor 64, and Kd represents a constant for the given circuit 22. Similarly, the following approximation provides the repetition rate for the oscillator 21,

N K5 fnd.

Cd-:nCa (=2, 3, 4)

Thus, capacitor 64 must be twice the value of capacitor 41, three times the value of capacitor 42, and four times the value of the capacitor 43.

From the foregoing relationships, it will be appreciated that by synchronizing the lower frequency or down beat oscillator 22 to produce its output in coincidence with one of the pulses of the high frequency or after beat oscillator 21, then the proper number of after beats will be produced in accordance with the above described functioning of the instant metronome. That is, for example, if the high frequency pulses are four times as fast as the low frequency pulses, then three after beats will be produced after each coincidence of a low frequency and high frequency pulse. Such coincidence it is noted will be evidenced by the longer duration pulse of the down beat -oscillator completely overshadowing the high frequency pulse, thereby producing the requisite audibly distinguishable down beat. I

In regard now to the means xfor synchronizing the two oscillators to perform as just described, it is seen that the base of the transistor 61 is coupled through a capacitor 71 an-d a diode 72 t-o the base of the transistor 34, with a resistor 73 connecting between the latter capacitor and diode and coupling to ground. The effect of coupling the oscillators 22 and 21 together in this manner is to tie down the high frequency oscillator 21 to produce pulses only in synchronization with the low frequency oscillator 22, in the required manner. More particularly, and referring now to FIGURE 3, down beat pulses 74 are represented on ya graph 76, the pulses 74 being negative because of the negative voltage supply and correspond to the output taken from the collector of the transistor 61. A generally sawtooth shaped pulse 77 is created at the base of the transistor 61, and is depicted on the graph 78 in FIGURE 3 as a trigger pulse. It is noted that the trigger pulse 77 produces a sharp peak coincident with the forward edge of the pulse 74.

The capacitor 71 serves to differentiate the pulse 77, so that a differentiated pulse 79 is created at the point of connection between the capacitor 71 and diode 72, the

pulse 79 being represented on the graph 81 in FIGURE 3. The differentiated pulse 79 then is coupled through the )diode 72 to the base `of the transistor 34 so that the oscillator 21 vis thereby forced to produce a pulse coincident with the pulse 79. Consequently, as represented in the graph 82, when the capacitor 41 is connected a series of after beat pulses 83 are produced at a repetition rate twice that of the down beat pulses 74, `and with the down beat pulse 74 being initiated substantially coincident with altern-ate ones of the pulses 83. Since the longer duration pulse 74 overrides the coincident pulse 83, only one pulse 83 is heard `and creates the single after beat which is interposed exactly midway between down beat pulses 74.

A phantom line representation in FIGURE 3 shows after beat pulses 83a having a repetition rate three times that of the down beat pulses 74, thereby causing two after beats to be interposed in equally spaced relation between each down beat,

The following table represents a typical set of components used in the above described circuitry.

T-33, 34, 46, 49, 61, 62 2Nl307 T-51 2N291 D-SS lN9l D-72 SD-9l R-31, 32 megohm 0 tol R36, 37, 66, 67 10K R-38, 68 100K C-39 nfd" 0.5 C-63 pfd" 2.0 C-64 /ifd 10.0 C-41 nfd 5.0 C-42 nfd 3.33 C-43 afd 2.5 C-71 pfd 0.02 R-73 4.7K R-69 68K R-44 47K C-52 ,afd 1.0 C-53 nf-d" 2.0 R-54 4.7K R-56 ohms 47()y R-47 1K S-23 volts 18 S29 do -3 It is noted from the above table that the capacitors 41, 42, and 43 are respectively '1/2, 1/3, and 1A the value of the capacitor 64, thus providing the above described relationship with regard to the repetition rates of the down beat and after beat oscillators. In addition, it is noted that the capacitor 63 is four times the value of the capacitor 39, thus making the duration of the down beat pulses approximately four times that of the after beat pulses.

It Will be appreciated that different pulse durations is only one way to produce audibly distinguishable sounds, and that numerous lother ways will occur to those skilled -in the art. For example, instead of coupling both of the oscillators 21 and 22 to the same audio oscillator 48, two separate audio oscillators of different frequencies could be provided, each being coupled to one of the oscillators 21 and 22. In the latter situation, the different sound frequency rather than the pulse duration would distinguish the down beats from the after beats. Similarly, separate audio stages could be provided for each or" the oscillators 21 and 22 so that the down beat had a greater volume than the after beats. Furthermore, the down beat oscillator could be coupled to trigger a bell or other audible pulse generator, thus making apparent the widespread possibilities of producing audibly distinguishable pulses as may be desired. It may also be noted that means other than the three capacitors 41, 42 and 43 may be used to adjust the frequency of the after beat oscillator to integer values of the down beat frequency. For example, instead of varying the capacitors as described, the resistances 31 and 32 may be adjusted appropriate to vary the frequencies of their respective oscillators to provide the requisite integer multiple relationship.

We claim:

1. An after beat metronome comprising, first and second lRC timed electronic multivibrator circuits each producing a regular periodic output pulse discernible from the other and with the frequency of one pulse being an integer multiplier of the other, with said rst multivibrator circuit providing the slower and said second multivibrator circuit providing the faster pulse respectively, means coupling said circuits for synchronizing said pulses for simultaneous starting time sequence, said iirst multivibrator circuit being formed to provide a pulse of longer duration than said faster pulse but in synchronism therewith whereby `said slower pulse provides the down beat and said faster pulses the after beats, a manually controlled switch and a plurality of capacitors connected for selection thereby in said second circuit providing after beat frequencies of Iselectable, integer multiples of said down beat frequency, and a pair of variable resistors one in each of said mulitvibrator circuits and gang connected for simultaneous manual operation and formed to provide on simultaneous yoperation equal ratio changes to their respective maximum resistance values for proportionally changing the frequencies of said down and after beats.

2. An after beat metronome as defined in claim 1, a third multivibrator circuit producing an audio signal, a gating transistor connected to the summed outputs of said rst yand second multivibrator circuits and to said third multivibrator circuit and utilizing said pulses for turning on and off said third multivibrator circuit, and an audio transducer connected to said third multivibrator circuit.

3. An after beat metronome as deiined in claim 2, and manually controlled means for suppressing the operation of said rst multivibrator circuit to provide a single beat mode operation.

References Cited by the Examiner UNITED STATES PATENTS 2,375,294 5/1945 Engel et al 58-130 2,522,492 9/1950 Andersen 324-68 2,848,616 8/1958 Tollefson 331-51 X 2,915,121 2/1959 Bloom 58-130` X 2,926,347 2/1960 Thiele 340-3 84 3,037,171 5/1962 Cerofolini 331-52 X FOREIGN PATENTS 940,322 10/ 1963 Great Britain.

NEIL C. READ, Primary Examiner.

I. J. LEVIN, Assistant Examiner. 

1. AN AFTER BEAT METRONOME COMPRISING, FIRST AND SECOND RC TIMED ELECTRONIC MULTIVIBRATOR CIRCUITS EACH PRODUCING A REGULAR PERIODIC OUTPUT PULSE DISCERNIBLE FROM THE OTHER AND WITH THE FREQUENCY OF ONE PULSE BEING AN INTEGER MULTIPLIER OF THE OTHER, WITH SAID FIRST MULTIVIBRATOR CIRCUIT PROVIDING THE SLOWER AND SAID SECOND MULTIVIBRATOR CIRCUIT PROVIDING THE FASTER PULSE RESPECTIVELY, MEANS COUPLING SAID CIRCUITS FOR SYNCHRONIZING SAID PULSES FOR SIMULTANEOUS STARTING TIME SEQUENCE, SAID FIRST MULTIVIBRATOR CIRCUIT BEING FORMED TO PROVIDE A PULSE OF LONGER DURATION THAN SAID FASTER PULSE BUT IN SYNCHRONISM THEREWITH WHEREBY SAID SLOWER PULSE PROVIDES THE DOWN BEAT AND SAID FASTER PULSES THE AFTER BEATS, A MANUALLY CONTROLLED SWITCH AND A PLURALITY OF CAPACITORS CONNECTED FOR SELECTION THEREBY IN SAID SECOND CIRCUIT PROVIDING AFTER BEAT FREQUENCIES OF SELECTICABLE INTEGER MULTIPLES OF SAID DOWN BEAT FREQUENCY, AND A PAIR OF VARIABLE RESISTORS ONE IN EACH OF SAID MULTIVIBRATOR CIRCUITS AND GANG CONNECTED FOR SIMULTANEOUS MANUAL OPERATION AND FORMED TO PROVIDE ON SIMULTANEOUS OPERATION EQUAL RATIO CHANGES TO THEIR RESPECTIVE MAXIMUM RESISTANCE VALUES FOR PROPORTIONALLY CHANGING THE FREQUENCIES OF SAID DOWN AND AFTER BEATS. 